Abstract: A terminal portion structure of an optical transmission element includes a light guiding component, glass protection layer and convex lens. The light guiding component includes a core and a cladding enclosing the core. The cladding is of a lower refractive index than the core, allowing light signals to be transmitted in the light guiding component by total internal reflection. The glass protection layer covers at least a terminal portion of the light guiding component. The convex lens is disposed on one side of the glass protection layer. The cross section of the terminal portion of the light guiding component tilts relative to the axial direction of the light guiding component. The optical axis of the convex lens is perpendicular to the axial direction of the light guiding component. The focal point of the convex lens is located at the cross section of the terminal portion of the core.

Abstract: A curved diffraction grating includes a substrate and a metal layer. The substrate is a two-dimensional curved plate structure and has a first surface, a second surface and a plurality of microstructures. The first surface is disposed opposite to the second surface, and the microstructures are disposed on the second surface. Each of the microstructures is a saw-tooth structure and has a clear blazed angle. The metal layer is disposed on the microstructures and has a plurality of diffraction structures corresponding to the microstructures. A spectrometer containing the curved diffraction grating and a manufacturing method of the curved diffraction grating are also disclosed.